UC Davis doctoral student and mosquito researcher Olivia Winokur remembers the defining moment when she learned that mosquitoes are “much more than just annoying.”

In fact, it was her childhood curiosity about a yellow fever vaccination that sparked her interest in mosquitoes.

In her youth, Olivia traveled with her parents and brothers to “off-the-beaten-path” locations. “So I was exposed to vector-borne disease awareness from a young age,” she recalled. “When I was 8 years old, I remember getting the yellow fever vaccination and being curious about why I had to get it for a trip to Southern Africa. I think that was my defining moment when I learned mosquitoes are more than just annoying. Since then, I've slept under many mosquito nets and am no stranger to mosquito bites.”

“I didn't think much about making a career out of those 'skeeters, though. I attended Cornell University as undergraduate, where I studied global public health from multiple perspectives. It wasn't until I became a research assistant in Dr. Laura Harrington's lab that I became fascinated with mosquito biology and decided to pursue a career in medical entomology.”

Winokur, who received her bachelor's degree in 2015 from Cornell University, majoring in Interdisciplinary Studies and focusing on the environmental effects on human health, enrolled in the UC Davis graduate program in 2016 as a Ph.D entomology student with a designated emphasis in the biology of vector-borne diseases.

She studies with major professor and UC Davis alumnus Christopher Barker, associate professor and associate researcher in the Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, who doubles as a graduate student advisor in the UC Davis Department of Entomology and Nematology.

Earlier this year, Winokur received a three-year National Science Foundation Graduate Research Fellowship. A 2017 Bill Hazeltine Memorial Award also helps fund her research.

Her research at UC Davis mainly involves Aedes aegypti, also known as the yellow fever mosquito. “At present, most of the research done on mosquito-borne virus transmission is done under a very narrow range of conditions that reflect a particular mosquito species' 'optimal' rearing and adult environment,” Winokur said. “I'm interested in how conditions outside of this optimal range at both the larval and adult stages affect mosquito-borne virus transmission. I work mostly with Aedes aegypti, which transmits diseases including dengue, Zika, yellow fever, and chikungunya viruses. Currently my research is focused on Zika virus. I hope to determine how the range of conditions mosquitoes encounter outside of the lab alter their life history traits, such as survival and blood feeding behavior, as well as viral transmission so that we can better understand geographical and seasonal mosquito-borne virus risk and eventually mitigate the risk.”

A typical day in the lab: “My days are usually a bit all over the place--I typically spend some time in the BSL-3 (Biosafety Level 3) either collecting samples from infected mosquitoes or processing previously collected samples, some time back in the lab analyzing data and writing, and I'm still taking classes so a few days a week I spend the afternoon on the main campus.”

What fascinates her about mosquitoes? “People are usually wowed when I tell them there are over 3500 species of mosquitoes!” she said. “But don't worry.. not all of them transmit human pathogens. I love telling people about the natural history of different genera and species and how this affects the likelihood of pathogen transmission to humans. I'm continually fascinated by how resilient mosquitoes are, how successful they've been throughout history, and how they've completely altered human history. I actually gave a lecture on how vector-borne diseases have altered human history last quarter (Winter 2018) to an undergraduate class led by UC Davis entomology graduate students (Ent10: Natural History of Insects).” 

Born in Long Beach, Calif., Olivia grew up in Laguna Niguel, Calif., where she focused on science as a part of the Dana Hills High School Health and Medical Occupations Academy. Olivia also played basketball at Dana Hills and helped the team win its first league title.

What drew her to UC Davis? “I grew up in California so I was familiar with UC Davis from a young age. I actually applied to UC Davis as an undergraduate, but decided to try life on the East Coast instead and attended Cornell University. While at Cornell, I learned a lot about UC Davis as most of my professors had spent some time at UC Davis during their academic tenure, and a lot of the research I was reading was coming out of UC Davis. I was excited to come back to the West Coast for graduate school so UC Davis seemed like an obvious choice!”

While at Cornell, she interned at the National Institutes of Health (NIH) in 2014, when advised by John Balbus of National Institute of Environmental Health Sciences (NIEHS), and Joshua Rosenthal, Fogarty International Center, where she coordinated and wrote an interagency proposal for climate change mitigation in middle and low-income countries under the United Nations. "I also helped develop a global clean cook stove implementation framework to advise NIH initiatives,” she said.

Winokur is a co-author of “The Impact of Temperature and Body-Size on Flight Tone Variation in the Mosquito Vector Aedes aegypti (Diptera: Culicidae): Implications for Acoustic Lures,"  published in April 2017, in the Journal of Medical Entomology. Several other manuscripts are accepted or in preparation.

She has given presentations at the Mosquito and Vector Control Association of California and the American Society of Tropical Medicine and Hygiene.

Dedicated to helping high school girls transition into STEM (Science, Technology, Engineering and Math) careers, Winokur is a founding board member and publicity co-chair of GOALS (Girls' Outdoor Adventure in Leadership and Science). The organization seeks “to cultivate and embolden the next generation of STEM leaders through a free, immersive, field-based summer science program for high school girls.”

“GOALS is for high school girls, inclusive of cis, trans, and gender nonbinary youth who identify with girlhood, to learn science hands-on while backpacking through the wilderness,” Winokur related. “I have worked with an incredible team of UC Davis affiliates to create GOALS to increase opportunities for high school students who identify with girlhood from backgrounds traditionally underrepresented in STEM. Our first trip is happening this summer!” This year's program takes place July 21 to Aug. 5.

Winokur is also a part of the Letters to a Pre-Scientist program “so I get to be a pen-pal to an elementary school student to talk about science!”  In addition, she serves as the treasurer of the UC Davis Entomology Graduate Student Association.

Delighted to return to California after being on the East Coast, Winokur spends her leisure time outdoors hiking and backpacking “and exploring the beautiful places near Davis like the Lake Tahoe area and Yosemite. I taught backpacking and wilderness survival skills for Cornell Outdoor Education during college. Additionally, I'm a trivia nerd so I watch a lot of Jeopardy! and play pub trivia with my entomology colleagues weekly. I also enjoy drawing, reading, playing board games, and doing jigsaw puzzles. When I get the chance I enjoy traveling as well--I just returned from Belize and I'll be in Denmark in July!”

After finishing her Ph.D., Winokur plans to remain in academia, but “I'm unsure exactly what that will look like! I really enjoy research, teaching, and mentoring so I'd like to have a career where I can do all of these. I also plan to have a career where I can conduct translational research with broad global health implications, engage non-scientists, create tools to help decision makers mitigate vector-borne disease burden worldwide, and encourage interest and diversity in STEM.” 

The annual UC Davis Research Symposium on the Designated Emphasis in the Biology of Vector-Borne Diseases (DEBVPD) will take place from 3 to 8 p.m., Thursday, May 3 in the Putah Creek Lodge, and will feature two speakers and a graduate student poster session.

Addressing the gathering will be Lark Coffey, member of the Department of Pathology, Microbiology and Immunology in the UC Davis School of Veterinary Medicine, and research director Stéphane Blanc of the program, Biology and Genetics of Plant-Pathogen Interactions at the Institut National de la Recherche Agronomique (INRA) in Montpellier, France. 

The event begins with opening remarks at 3:10, followed by Coffey's presentation at 3:20 on “Contrasting Virulence and Transmissibility in Disparate hosts: A Zika Virus Mutation that Associates with Fetal Death in Rhesus Macaques reduces transmission by Aedes aegypti Mosquitoes.” 

The graduate student poster session begins at 4:05 p.m., with Laura Backus, Nicholas Booster, Marisa Donnelly, Jessica Franco, Karen Holcomb, William Louie, Risa Pesapane, Benjamin Plourde, Maribel Portilla, Jennifer Reed, Kasen Riemersma, Pascale Stiles and Olivia Winokur presenting. Blanc's address follows at  5:30 p.m. on "Current Research Trends in the Interaction between Plant Viruses and Insect Vectors."

A dinner (space is limited and reservations are required) will follow at 6:15, announced Professor Sharon Lawler of the UC Davis Department of Entomology and Nematology and chair of DEBVBD.

Coffey focuses her research on the ecology and evolution of arthropod-borne viruses, including Zika, West Nile and chikungunya. They are significant causes of human disease, with no vaccines or treatments beyond palliative care.

Her team seeks to understand patterns of viral molecular evolution in enzootic and epidemic settings and the viral genetic factors that promote emergence of epidemic variants via host range changes. Studies also focus on how intrahost arboviral genetic diversity generated by error-prone viral replication to produce minority variants influences infectivity and transmissibility in mosquito and vertebrate hosts. The team is also developing approaches to improve arbovirus surveillance.

Coffey received her bachelor's degree in biology at the University of the South, Sewanee, Tenn., and her doctorate in experimental pathology from the University of Texas Medical Branch in Galveston, Texas. She then conducted research at the Institut Pastuer in Paris, France, and at the University of San Francisco.

Blanc has been with INRA Montpellier since 1997 and with his current research unit since 2004. He studies interactions among viruses, insect vectors and plant hosts. His group works at multiple scales from molecular to viral genetics and population dynamics. In addition, he has an innovative focus on understanding multipartite viruses.

He received his undergraduate degree in biology of populations and organisms from the University of Montpellier. His doctoral research, also at the University of Montpellier, addressed molecular mechanisms of plant virus transmission by insect vectors. After receiving his doctorate in 1993, he studied plant virus vector-transmission at the University of Kentucky, Lexington, with Professor T. P. Pirone.

For more information on the symposium, contact Sharon Lawler at splawler@ucdavis.edu. For information on dinner reservations, access https://bit.ly/2HanMrt.

The Department of Entomology and Nematology and the Department of Plant Pathology are home to the Designated Emphasis in the Biology of Vector-borne Diseases (DEBVBD).

DAVIS--Noted molecular neurobiologist Leslie Vosshall of the Rockefeller University, New York City, will speak on "Neurobiology of the World's Most Dangerous Animal"--the mosquito--at a seminar set for 4:10 p.m., Wednesday, May 24 in the Student Community Center, UC Davis. 

The Vosshall laboratory studies the molecular neurobiology of mosquitoes. Female mosquitoes require a blood meal to complete egg development, she explains. "In carrying out this innate behavior, mosquitoes spread dangerous infectious diseases such as malaria, dengue, Zika, Chikungunya and yellow fever."

She further explains: "Humans attract mosquitoes via multiple sensory cues including emitted body odor, heat, and carbon dioxide in the breath. The mosquito perceives differences in these cues, both between and within species, to determine which animal or human to target for blood-feeding. We have developed CRISPR/Cas9 genome-editing in the Aedes aegypti mosquito with the goal of understand how sensory cues are integrated by the female mosquito to lead to host-seeking behavior."

"Some of the questions we are currently addressing are: Why are some people more attractive to mosquitoes than others? How do insect repellents work? How are multiple sensory cues integrated in the mosquito brain to elicit innate behaviors? How do female mosquitoes select a suitable body of water to lay their eggs? The long-term goal of all of our work is to understand how behaviors emerge from the integration of sensory input with internal physiological states."

The seminar, open to all interested persons, is sponsored by the College of Biological Sciences and the Storer Life Sciences Endowment. Host is molecular geneticist Joanna Chiu, assistant professor, UC Davis Department of Entomology and Nematology.

At the Rockefeller University, Vosshall is the Robin Chemers Neustein Professor and head of the Laboratory of Neurogenetics and Behavior and director of the Kavli Neural Systems Institute. She is known for her work on the genetic basis of chemosensory behavior in both insects and humans.

Her notable contributions to science include the discovery of insect odorant receptors, and the clarification of general principles regarding their function, expression and the connectivity of the sensory neurons that express them to primary processing centers in the brain. She founded the Rockefeller University Smell Study in 2004 with the goal of understanding the mechanisms by which odor stimuli are converted to olfatory percepts.

Vosshall received her bachelor's degree in biochemistry from Columbia University, New York, in 1987 and her doctorate from Rockefeller University in 1993. Following postdoctoral work at Columbia University, she joined the Rockefeller faculty in 2000.

She is the recipient of the 2008 Lawrence C. Katz Prize from Duke University, the 2010 DART/NYU Biotechnology Award, and the 2011 Gill Young Investigator Award. She is an elected fellow of the American Association for the Advancement of Science and a member of the National Academy of Sciences.

For more information on the seminar, contact host Joanna Chiu at jcchiu@ucdavis.edu.

DAVIS--UC Davis medical entomologist Anthony Cornel, Ph.D. is targeting the potential spread of the Zika virus mosquito vector, Aedes aegypti, using a novel control strategy that renders the female mosquitoes sterile. 

Male Aedes aegypti mosquitoes infected with a bacterium, Wolbachia pipientis, are being released in Clovis, Fresno County, where this mosquito was discovered in June 2013. Although this mosquito is now found in California, there has been no locally transmitted case of the Zika virus in the state. 

The project, to determine dispersal and survival, began Monday, May 10.

“The daytime-biting mosquito, which feeds predominantly on humans, has spread to at least seven counties since its discovery in Clovis,” said Cornel, a mosquito researcher and faculty member with the UC Davis Department of Entomology and Nematology and the UC Kearney Agricultural Research and Extension Center, Parlier. 

“The biting nuisance and potential of the mosquito Aedes aegypti to transmit Zika, Chikungunya and dengue viruses in California is cause for concern,” he said. “Efforts to curb its spread and reduce populations have not been very effective. Control efforts have included educating the public to remove standing water (source reduction) insecticide barrier sprays and bacterial larviciding.”

The collaborative effort involves Steve Mulligan, director of the Consolidated Mosquito Abatement District, based in Fresno County; Stephen Dobson of the University of Kentucky; MosquitoMate Inc, (mosquitomate.com); and UC Davis. The researchers will evaluate the population suppressive ability of the novel sterile insect technique, which is part of a comprehensive vector management approach.

Only Aedes aegypti is targeted. “When the Wolbachia-infected male mosquito mates with non-infected females, the result is “cytoplasmic incompatibility, which causes the female to lay infertile eggs that will not hatch,” Cornel explained.

“This approach requires the release of tens of thousands of Wolbachia-infected males into residential neighborhoods where this mosquito is a nuisance,” the medical entomologist said. “Releasing large numbers of males increases the chance that an introduced male will mate with the native females.”

Although residents will notice increased numbers of male mosquitoes, male mosquitoes do not bite and cannot transmit disease. Both U.S,federal and State regulatory agencies have approved the technique for evaluation of effectiveness.

“This sterile insect technique was evaluated in 2015 in Los Angeles to suppress another invasive mosquito, Aedes albopictus,” Cornel said, adding that the results from that trial look promising.

The Zika virus, now spreading throughout the Western hemisphere, was first identified in Uganda in 1947 in rhesus monkeys, according to the World Health Organization. It was subsequently identified in humans in 1952 in Uganda and the United Republic of Tanzania. Outbreaks of Zika virus disease have been recorded in Africa, the Americas, Asia and the Pacific. 

Despite the mosquito's invasion into new areas of the United States, there are no reported cases of locally transmitted Zika virus in California or in the contiguous United States, according to the Centers for Disease Control and Prevention. The cases have all involved travelers returning home from countries plagued with disease outbreaks. 

“We can't predict how far this mosquito will spread in California,” said Cornel, noting that its range has expanded “south of Fresno to San Diego. The farthest site north is Madera in the Central Valley, but it's also been found in the more coastal area of Menlo Park in San Mateo.”

It's troubling that the mosquito is becoming more and more resistant to pesticides, said Cornel, who collects, rears and researches mosquitoes from all over the world, including the United States, Mali, Cameroon, Comoros, Tanzania, South Africa and Brazil.

“We have found that Aedes aegypti have insecticide resistance genes which likely explains why the use of ultra-low volume and barrier spray applications for control have not worked as well as expected.”